## Re: Primes from permutation of prime digits

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• ... Scrap that. It s not that surprising to me anymore. :) Mark
Message 1 of 7 , Feb 13, 2009
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<mark.underwood@...> wrote:
>

> Interesting. It's surprising to me that the number of odd digits
> barely outnumbers the number of even digits in these primes with
> maximum perms. Must be a good reason ...
>

Scrap that. It's not that surprising to me anymore. :)

Mark
• I prefer zak(1123465789) = 152526 to zak(1023345679) = 156227 since the former does not invoke leading zeros. David
Message 2 of 7 , Feb 14, 2009
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I prefer
zak(1123465789) = 152526 to
zak(1023345679) = 156227 since
the former does not invoke leading zeros.

David
• ... Thereafter, 11-digit primes become somewhat memory-intensive, in my simple-minded implementation, using GP s vecsort . Might Zak and/or Maximilian confirm
Message 3 of 7 , Feb 14, 2009
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> I prefer
> zak(1123465789) = 152526 to
> zak(1023345679) = 156227 since
> the former does not invoke leading zeros.

Thereafter, 11-digit primes become somewhat memory-intensive,
in my simple-minded implementation, using GP's "vecsort".

Might Zak and/or Maximilian confirm that
zak(10123457689) = 1404250
without duplication of primes, but allowing Zak's leading zeros ?

David
• ... yes: zak(10123457689) %1 = 2808500 2808500/2 (symmetry factor for exchange of the two 1 s) %2 = 1404250 Maximilian
Message 4 of 7 , Feb 15, 2009
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> Thereafter, 11-digit primes become somewhat memory-intensive,
> in my simple-minded implementation, using GP's "vecsort".
>
> Might Zak and/or Maximilian confirm that
> zak(10123457689) = 1404250
> without duplication of primes, but allowing Zak's leading zeros ?

yes:
zak(10123457689)
%1 = 2808500
2808500/2 \\ (symmetry factor for exchange of the two 1's)
%2 = 1404250

Maximilian
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